This invention relates to a system for treating water and more particularly to a method and apparatus for treating drinking water through intense aeration to cause the oxidation and precipitation of certain contaminants such as iron, manganese and arsenic.
Precipitation of contaminants is an important step in the treatment of drinking water. Typical devices that use aeration and oxidation to precipitate impurities include devices that use strike plates and baffles within mixing vessels to serve as collectors of sediment and to increase travel path and surface area for air/water interaction. For example Dieter, U.S. Pat. No. 5,494,583, discloses supplying air by Venturi action or pressurized air source to a mixing device. A series of baffles within the mixing device causes the air bubbles to reduce in size and mix with the water. This type of device relies on the baffles to cause mixing of the water and to provide sufficient surface area. While the specification discloses that precipitates are carried out of the mixing device by the flow of water it is known in the art that devices incorporating such baffles require frequent backwashing or other cleaning procedures to remove sediment.
Schlafer et al, U.S. Pat. No. 5,725,759, discloses a similar device that uses numerous perforated plastic balls to mix water within the mixing vessel and to provide increased surface area for air/water interaction. Such devices also require frequent cleaning to remove sediment. The patents to St. Pierre, U.S. Pat. Nos. 5,460,731 and 5,601,724, disclose a method whereby a stream of water is forced against an impaction target such as the top inner surface of the pressure vessel. The water then cascades through the vessel, first striking a plate and then striking the surface of liquid accumulated in the bottom of the vessel. Along with the problems of sediment buildup, such devices typically also cause a significant pressure drop in the water line.